A control of a source device has been suggested in which a CEC (Consumer Electronics Control) command such as a power-supply ON command is transmitted with respect to the source device from a link device in an image display system that uses the source device (for example, a hard disk recorder, a DVD player or set-top box) based on the standard of HDMI and the link device (for example, a projector or a television).
For example, Japanese Patent Publication No. 2008-79135 describes a transmitting method of the CEC command such as the power-supply ON command with respect to the source device that is selected by a user in one of the set-top box or the DVD player that is connected to a liquid crystal display device in a state where the liquid crystal display device is activated. In a case where such a method is used, generally the user selects a desired source device in a state that a list of source devices that is connected to the link device is displayed.
However, in the projector, since the time during which the image is to be in a displayable state is relatively long compared to a display device such as a television, the time taken in the method is excessively long in a case where the activation of the projector occurs in tandem with the activation of the source device.
Also, in the case where the activation of the projector occurs in tandem with the activation of the source device, a transmitting method of the power-supply ON command with respect to the projector when the source device is activated is considered. However, since the source device takes along time to activate the hard disk recorder, the time during which the image is to be in a projectable state in the method is relatively long compared to a transmitting method of the power-supply ON command with respect to the source device when the projector is activated.
Further, in a situation in which a plurality of source devices is connected to the projector, the projector needs to select a suitable source device among a plurality of source devices and activate it so that the activation of the projector might occur in tandem with the activation of the source device.